Mitha Hardianni,2013 Problem Based Learning To Enhance Students’ Critical Thinking Skills And Concept Comprehension In
Pollution Concept Universitas Pendidikan Indonesia
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G. Collecting Data Technique
To collect data some steps done the steps are including gave pre test first before implementation of Problem Based Learning then analyze the result of pretest,
gave treatment by using Problem Based Learning during that process data were taken based on observation sheet, gave post test then analyze the result of posttest,
gave questionnaire to students and the last had interview with Biology teacher.
H. Data Analysis Techniques
1. Scoring
Gave score to students‟ concept comprehension and critical thinking skill test. For concept comprehension test gave score 1 for right answer and 0 for false
answer while for critical thinking skill test used scoring guide. The formula used to convert score into percentage as follow:
After percentage of students‟ score were obtained, it can be classified based on
score percentage category according to Arikunto as follow:
Table 3.5 Category of student score Percentage
Category
76-100 Good
56-75 Sufficient
40-55 Poor
0-39 Very poor
Source: Arikunto, 2012
Student’s score = x 100
Mitha Hardianni,2013 Problem Based Learning To Enhance Students’ Critical Thinking Skills And Concept Comprehension In
Pollution Concept Universitas Pendidikan Indonesia
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2. Gain and Normalized Gain
To find out the difference between pretest and posttest score can use gain formula. The formula which is used to calculate the gain value is:
Hake, 1998 With:
= gain = post test score
= pretest score To see the improvement of students‟ concept comprehension and critical
thinking skill used normalized gain as it shown as formula below:
Hake, 1999 With:
= normalized gain = posttest score
= pretest score
Normalized gain value which is obtained will be interpreted into gain index category according to Hake in table 3.7:
Mitha Hardianni,2013 Problem Based Learning To Enhance Students’ Critical Thinking Skills And Concept Comprehension In
Pollution Concept Universitas Pendidikan Indonesia
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Table 3.6 N-gain index category
Hake, 1999
3. Analysis of Problem Based Learning implementation
To measure the successful of implementation learning process used the formula below:
Percentage of implementation = Ʃ observer answer x 100
Ʃ amount observer
After percentage of implementation was obtained, researcher interpreted the data into category in table 3.8 below:
Table 3.7 Percentage of learning implementation category Percentage
Category
80 or more Very good
60-79 Good
40-59 Sufficient
21-39 Low
0-20 Very low
Ridwan, 2000
N-Gain Category
g 0,7 High
0,3 g 0,7 Medium
g 0,3 Low
Mitha Hardianni,2013 Problem Based Learning To Enhance Students’ Critical Thinking Skills And Concept Comprehension In
Pollution Concept Universitas Pendidikan Indonesia
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4. Students response analysis
To analyzed students response in learning process through Problem based
Learning used formula as following:
Percentage of stu dents‟ response = Ʃ students who answer „yes‟ x 100
Ʃ amount students
5. Interview analysis
Analyze interview result of teacher‟s opinion toward Problem Based Learning
I. The Result of Trial Test Instrument
The instruments were tested before it is used in this research. It is tested to grade XI of senior high school at one international school in Tanggerang who
already learned the same topic. There are two kinds of test that are used those are multiple choice containing 34 items and essay containing 18 items.
From trial instrument result, researcher analyzed the result to get validity, reliability, difficulty level and discriminating power. For concept comprehension
test item were analyzed by using ANATES pilihan ganda Version 4.1.0, meanwhile critical thinking test were analyzed by using ANATES uraian Version 4.0.7. The
recap result of validity, discriminating power and difficulty level of concept comprehension can be seen on table below.
Table 3.8 Recapitulation of validity concept comprehension test Category
Question number
High 5,7,11,17,22,24,26,32,33,34
Sufficient 13,20,29
Low 1,3,8,9,14,16,19,21,28
Mitha Hardianni,2013 Problem Based Learning To Enhance Students’ Critical Thinking Skills And Concept Comprehension In
Pollution Concept Universitas Pendidikan Indonesia
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Category Question number
Very Low 4,10,12,15
Invalid 2,6,18,23,25,27,30,31
Table 3.9 Recapitulation of discriminating power concept comprehension test
Category Question number
Excellent 7,11,17,26,33,34
Good 5,13,1421,22,24,29,32
Sufficient 3,4,8,12,16,19,20,28
Poor 1,29,1015
Not Appropriate 6,18,23,25,27,30,31
Table 3.10 Recapitulation of difficulty level concept comprehension test
F o
r
Recapitulation of validity, discriminating power and difficulty level of critical thinking skills illustrated in the following table below.
Table 3.11 Recapitulation of validity critical thinking skills test Category
Question number
High 2a,2b,6a,6b
Category Question number
Very Difficult 6,18,25,27,30,31
Difficult 12,23
Fair 7,10,11,15,17,19,26
Easy 4,5,8,9,13,14,16,20,21,22,24,32,33,34
Very Easy 1,2,3,29
Continue Table 3.8 Recapitulation of validity concept comprehension test
Mitha Hardianni,2013 Problem Based Learning To Enhance Students’ Critical Thinking Skills And Concept Comprehension In
Pollution Concept Universitas Pendidikan Indonesia
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Category Question number
Sufficient 2d,3,4a,5b,7b,7c
Low 2c,4b,7a
Very Low 1a,1b,1c,5a
Invalid -
Table 3.12 Recapitulation of discriminating power critical thinking skills test
Category Question number
Excellent 6c
Good 2a,2b,2d,36a,6b
Sufficient 2c,4a,4b,5b,7c
Poor 1a,1b,1c,5a,7a,7b
Not Appropriate -
Table 3.13 Recapitulation of difficulty level critical thinking skills test
Based on Concept comprehension trial test were obtained that reliability value of instruments is as much as 0.81 which include as very high category.
Meanwhile in critical thinking skills test reliability value is 0.75 which include as high category. Thus, it showed that those test are qualified to be used.
Category Question number
Very Difficult -
Difficult 2a,7c
Fair 1c,2b,2c,2d,3,4a,5a,5b,6a,6b,6c,7a
Easy 1a,7b
Very Easy 1b,4b
Continue Table 3.11 Recapitulation of validity critical thinking skills test
Mitha Hardianni,2013 Problem Based Learning To Enhance Students’ Critical Thinking Skills And Concept Comprehension In
Pollution Concept Universitas Pendidikan Indonesia
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J. Research Procedure
